1. Field of the Invention
The present invention, temperature sensor using two fiber Bragg gratings, improves the accuracy of a well known traditional fiber grating temperature sensor. It can also be used with other fiber biomedical sensors or environmental sensors for calibration.
2. Description of the Related Art
Fiber optic temperature sensors have been extensively studied since 1980. Different types of fiber optics sensors can be used to measure temperature in many areas due to the following advantages of fiber optics: compactness and smallness, resistance to chemical corrosion, immunity to electromagnetic interference and biocompactibility, etc. So they are excellent candidates as bio-temperature sensors. Currently it is common to combine fiber optics and chemical sensor to make a biomedical signal sensor in the development of medical sensors. The spectral changes at the chemical sensor head is detected and analysis outside the body through the transmission of fiber optics. Basically these types of sensors all required temperature calibrations in order to work properly. The accuracy of temperature measurement is of vital importance.
The present invention use two fiber optic gratings to achieve accurate temperature measurement and calibration. Its performance is not affected by frequency drifting. Furthermore, no thermocouple is needed in the biomedical sensor package. The biomedical sensors will be all optical and miniaturized because the temperature sensor is made of fiber optics.